Very little is known about the state-listed small mammals in Massachusetts.
The Rock Shrew is a habitat specialist found at higher elevations, especially in areas of rock jumble below exposed rock ledges. This shrew was found in Massachusetts in 1911 on Mt. Greylock. Since then, only nine individuals have been documented at three locations in Berkshire County. This small shrew lives below ground most of its life, and is very difficult to find unless specifically looked for. As long as higher elevation habitats remain protected, this shrew will likely remain secure.
The Water Shrew is also secretive and hard to find, but has more records than the Rock Shrew. The Water Shrew has been documented in six counties in central and western Massachusetts along the edges of streams and beaver swamps. The Wetlands Protection Act helps protect the habitat of this species.
The Pygmy Shrew (not state-listed) is the smallest mammal in Massachusetts, and has only been found once in the state. The only specimen documented in Massachusetts is was found drowned in a discarded beer bottle in 1991 on Mt. Greylock. Similar to the Rock Shrew, this species is likely secure in areas of protected habitat.